WO2019225668A1

WO2019225668A1 - Imaging element and imaging device

Info

Publication number: WO2019225668A1
Application number: PCT/JP2019/020350
Authority: WO
Inventors: 良次安藤; 高木　徹; 周太郎加藤; 佳之渡邉; 崇志瀬尾
Original assignee: 株式会社ニコン
Priority date: 2018-05-23
Filing date: 2019-05-22
Publication date: 2019-11-28
Also published as: CN112352420B; US20210314512A1; JP7047907B2; CN116528070A; JP2022078348A; CN112352420A; JP7363947B2; US11910113B2; JPWO2019225668A1

Abstract

This imaging element comprises: a first photoelectric conversion unit that photoelectrically converts light and generates a charge; a first output unit that outputs a first signal based on the charge generated by the first photoelectric conversion unit; a plurality of second photoelectric conversion units that photoelectrically convert light and generate a charge; a plurality of second output units that output second signals based on the charges generated by the second photoelectric conversion units; an output line by which the first output unit and the plurality of second output units are connected, and by which the first signal and/or the second signals are output; a first control line that is for controlling the output of the first signal from the first output unit to the output line; and a second control line that is for controlling the output of the second signals from the plurality of second output units to the output line.

Description

Imaging device and imaging apparatus

The present invention relates to an imaging element and an imaging apparatus.

2. Description of the Related Art Conventionally, there is known an image sensor that adds and reads signals from a plurality of pixels (for example, Patent Document 1). However, the conventional image sensor cannot obtain a signal obtained by adding signals of arbitrary plural pixels.

Japanese Unexamined Patent Publication No. 2013-143730

According to the first aspect, the image sensor photoelectrically converts light to generate a charge, and a first output that outputs a first signal based on the charge generated by the first photoelectric converter. A plurality of second photoelectric conversion units that photoelectrically convert light to generate charges, a plurality of second output units that output second signals based on the charges generated by the second photoelectric conversion units, An output line connected to the first output unit and a plurality of the second output units to output at least one of the first signal and the second signal; and the first output unit to the output line. A first control line for controlling the output of one signal, and a second control line for controlling the output of the second signal from the plurality of second output units to the output line.
According to the second aspect, the imaging apparatus includes the imaging element according to the first aspect and a generation unit that generates image data based on the second signal.

Sectional drawing which shows the structure of an imaging device typically The top view which looked at the image sensor from the image pick-up side. FIG. 2A is an overall view of the image sensor, and FIG. 2B is an enlarged view of a part thereof. The circuit diagram of the pixel of an image sensor, and a readout circuit. Sectional drawing of an image pick-up element. Sectional drawing of an imaging pixel and a pixel for focus detection.

(Embodiment of Imaging Device)
FIG. 1 is a cross-sectional view schematically showing a configuration of an imaging apparatus using the imaging device according to the first embodiment. The imaging device 1 includes an imaging optical system 2, an imaging element 3, a control unit 4, a lens driving unit 5, and a display unit 6.

The imaging optical system 2 forms a subject image on the imaging surface of the image sensor 3. The imaging optical system 2 includes a lens 2a, a focusing lens 2b, and a lens 2c. The focusing lens 2b is a lens for adjusting the focus of the imaging optical system 2. The focusing lens 2b is configured to be movable in the optical axis Z direction.

The lens driving unit 5 has an actuator (not shown). The lens moving unit 5 moves the focusing lens 2b in the optical axis Z direction by this actuator. The image sensor 3 captures a subject image and outputs a signal. The imaging element 3 has an imaging pixel and an AF pixel (focus detection pixel). The imaging pixel outputs a signal (image signal) used for image generation. The AF pixel outputs a signal (focus detection signal) used for focus detection. The control unit 4 controls each unit such as the image sensor 3. The control unit 4 performs image processing or the like on the image signal output from the imaging device 3 to generate image data. The control unit 4 records image data on a recording medium (not shown), and displays an image based on the image data on the display unit 6. The control unit 4 can also be interpreted as a generation unit that generates an image based on the image signal. The display unit 6 is a display device having a display member such as a liquid crystal panel.

Further, the control unit 4 performs a focus detection process necessary for automatic focus adjustment (AF) of the imaging optical system 2 by a known phase difference detection method. Specifically, the control unit 4 detects the in-focus position of the focusing lens 2 b for forming an image by the imaging optical system 2 on the imaging surface of the imaging element 3. The control unit 4 detects the image shift amount between the first and second images based on the pair of focus detection signals output from the image sensor 3. The control unit 4 calculates a deviation amount (defocus amount) between the current position of the focusing lens 2b and the in-focus position based on the detected image shift amount. Focusing adjustment is automatically performed by driving the focusing lens 2b in accordance with the defocus amount.

(Embodiment of imaging device)
FIG. 2A is a diagram of the image sensor 3 according to the embodiment of the present invention as viewed from the imaging surface side, that is, from the −Z side in FIG. The imaging element 3 has a plurality of pixels 30 arranged in the x direction and the y direction in FIG. Although a part of the pixel 30 is omitted in FIG. 2, a large number of pixels 30 may be arranged in the x direction and the y direction, for example, 1000 or more.
A horizontal control unit HC is provided at the left end in the figure, and a vertical control unit VC is provided at the upper end in the figure in an area (imaging area) in which a plurality of pixels 30 are arranged.

The image sensor 3 has a plurality of pixel blocks BC. In FIG. 2, one pixel block BC has a plurality of pixels 30 arranged in the x direction and the y direction, which are surrounded by a boundary line BB indicated by a broken line. As will be described later, the output units of the plurality of pixels 30 in each of the pixel blocks BC are connected to one output line and connected to one readout unit. The plurality of pixels 30 in each of the pixel blocks BC may be connected to a plurality of output lines and connected to a plurality of readout units.
In FIG. 2, a portion corresponding to one pixel block BC is hatched for easy explanation. However, each area surrounded by each boundary line BB indicated by a broken line is a pixel block BC. The plurality of pixels 30 are divided and arranged in a plurality of pixel blocks BC.

In the case of the example shown in FIG. 2, a total of 16 pixels 30 arranged in the x direction and 4 in the y direction constitute one pixel block BC.
The number of pixels arranged in the x direction and y direction in one pixel block BC is not limited to four, and may be other numbers such as six or eight. The number of arrays may be different between the x direction and the y direction.
In addition, the outline shape of the pixel block BC is not limited to the rectangle illustrated in FIG. 2, and may be an arbitrary shape including a plurality of pixels 30. In this case, the shape of the boundary line BB is not a simple straight line but a shape in which a plurality of straight lines are bent and connected.

FIG. 2B is an enlarged view showing two pixel blocks BC1 and BC2 adjacent in the x direction among the pixel blocks BC shown in FIG.
As shown in FIG. 2B, each of the plurality of pixels 30 includes any one of three color filters (color filters) having different spectral characteristics of R (red), G (green), and B (blue), for example. Provided. The R color filter mainly transmits light in the red wavelength region, the G color filter mainly transmits light in the green wavelength region, and the B color filter mainly transmits light in the blue wavelength region. . The pixel has different spectral characteristics depending on the arranged color filter. The pixel 30 includes a pixel having sensitivity to red (R) light (hereinafter referred to as R pixel R), a pixel having sensitivity to green (G) light (hereinafter referred to as G pixel G), and blue. Some pixels (B) have sensitivity to light (hereinafter referred to as B pixels B). These pixels 30 are arranged in a so-called Bayer array. The G pixel Gb is a G pixel arranged in the same x direction as the B pixel B, and the G pixel Gr is a G pixel arranged in the same x direction as the R pixel R.

The pixel block BC1 has four G pixels Gb, G pixels Gr, R pixels R, and B pixels B arranged in a Bayer array. These pixels 30 are imaging pixels Gb, Gr, R, and B (hereinafter collectively referred to as imaging pixels 30c) that are used for imaging an optical image formed on the imaging surface of the imaging device 3. is there.

The arrangement of the pixels 30 in the pixel block BC2 is substantially the same as that of the pixel block BC1, but in the pixel block BC1, some of the pixels where the B pixel B is arranged are different from the above-described imaging pixel 30c. They are replaced with different special pixels Z1 and Z2 (also collectively referred to as special pixels ZZ).

The special pixel ZZ is, for example, an AF pixel, and the configuration thereof will be described later.
The special pixel ZZ is not limited to the AF pixel, and may be a pixel whose sensitivity is different from any of the imaging pixels 30c described above. Moreover, the pixel which has a color filter in which spectral characteristics differ from any of the above-mentioned imaging pixels 30c may be sufficient.
The special pixel ZZ can also be interpreted as the first pixel. On the other hand, the imaging pixel 30c can also be interpreted as a second pixel.

The pixel block BC2 includes at least one special pixel ZZ as a plurality of pixels 30, and includes a plurality of imaging pixels 30c.
At least one pixel block BC among the plurality of pixel blocks BC is configured by at least one special pixel ZZ and a plurality of imaging pixels 30c as in the pixel block BC2. At least one pixel block BC among the plurality of pixel blocks BC may be entirely configured by the imaging pixels 30c like the pixel block BC1.

From the vertical control unit VC shown in FIG. 2A, vertical selection lines VS1 to VS8 (collectively referred to as vertical selection lines VS) connected to a selection unit TV described later of each pixel 30 are in the y direction. It extends to. From the horizontal control unit HC, horizontal selection lines HS1 to HS4 (collectively referred to as horizontal selection lines HS) connected to a selection unit TH2 described later of each imaging pixel 30c extend in the x direction. From the horizontal control unit HC, a special horizontal selection line ZS connected to a selection unit to be described later of each special pixel Z1 and Z2 extends in the x direction.

As shown in FIG. 2B, each of the vertical selection lines VS1 to VS8 is shared by a plurality of pixels 30 arranged in the y direction, and each of the horizontal selection lines HS1 to HS4 is a plurality of pixels arranged in the x direction. It is shared by the imaging pixel 30c. The special horizontal selection line ZZ is shared by a plurality of special pixels ZZ arranged in the x direction.

3 shows four pixels 30 (two in the vertical direction and two in the horizontal direction) surrounded by a two-dot chain line PB in the lower right in the pixel block BC2 shown in FIG. It is an enlarged view which shows the outline | summary of an electric circuit. As shown in the two-dot chain line PB in FIG. 2B, the four pixels 30 are the G pixel Gb in the upper left, the special pixel Z2 in the upper right, the R pixel R in the lower left, and the G pixel Gr in the lower right.
Each of the four pixels (Gb, Z2, R, Gr) is basically a so-called four-transistor type CMOS image sensor, but, as will be described later, the so-called selection transistor configuration is a normal four-transistor type CMOS. This is different from the type image sensor.

In each pixel (Gb, Z2, R, Gr), the photodiode PD as a photoelectric conversion unit photoelectrically converts incident light to generate charges, and temporarily stores the generated charges. The transfer transistor TX transfers the charge accumulated in the photodiode PD to the floating diffusion (FD) region FD in which the capacitor CC is formed based on a transfer signal sent to the gate from a transfer control line (not shown). . The amplification transistor TA outputs a signal corresponding to the electric charge generated by the photodiode PD when a voltage generated in the FD region FD by the transferred electric charge is applied to the gate thereof.

The power supply voltage VDD is applied to the input side (drain) of the amplification transistor TA. The reset transistor TR resets the voltage of the FD region FD to the power supply voltage VDD by discharging the charge of the FD region FD to the power supply voltage VDD side.

The output side (source side) of the amplification transistor TA of each pixel (Gb, Z2, R, Gr) is connected to the input side of the vertical selection transistor TV. The gate of the vertical selection transistor TV is connected to the vertical selection line VS7 or VS8, and the vertical selection transistor TV is turned on or off according to a control signal sent from the vertical control unit VC shown in FIG. It becomes.

The output side of the vertical selection transistor TV of the imaging pixel (Gb, R, Gr) is connected to the input side of the horizontal selection transistor TH2. The gate of the horizontal selection transistor TH2 is connected to the horizontal selection line HS3 or HS4, and the horizontal selection transistor TH2 is turned on or off by a control signal sent from the horizontal control unit HC shown in FIG. It becomes.

In the imaging pixels (Gb, R, Gr) of the imaging device 3 of the embodiment, one or both of the horizontal selection transistor TH2 and the vertical transistor TV are output from the imaging pixel (Gb, R, Gr) (second pixel). The output unit can be interpreted as a second output unit).
Alternatively, the amplification transistor TA can be interpreted as an output unit (second output unit). The second output unit may include the amplification transistor TA and one or both of the horizontal selection transistor TH2 and the vertical transistor TV.

On the other hand, the output side of the vertical selection transistor TV of the special pixel Z2 is connected to the input side of the special horizontal selection transistor TH1. The gate of the special horizontal selection transistor TH1 is connected to the special horizontal selection line ZS, and the special horizontal selection transistor TH1 is turned on or off by a control signal sent from the horizontal control unit HC shown in FIG. It becomes conduction.

In the special pixel Z2 of the imaging device 3 of the embodiment, one or both of the special horizontal selection transistor TH1 and the vertical transistor TV can be interpreted as an output unit (the first output unit as the output unit of the first pixel).
Alternatively, the amplification transistor TA can be interpreted as an output unit (first output unit). The second output unit may include the amplification transistor TA and one or both of the horizontal selection transistor TH1 and the vertical transistor TV.

The special horizontal selection line ZS controls the first output unit (selection transistor TH1) that is the output unit of the first pixel (special pixel ZZ), and therefore can be interpreted as a first control line.
Further, since the horizontal selection line HS controls the second output unit (selection transistor TH2) that is the output unit of the second pixel (imaging pixel 30c), it can also be interpreted as a second control line.
Further, the vertical selection line VS can be interpreted as a third control line.

The output part of the horizontal selection transistor TH2 of the imaging pixel (Gb, R, Gr) in the pixel block BC2 and the output part of the special horizontal selection transistor TH1 in the special pixel Z2 in the pixel block BC2 are all one output line. Connected to RW. The output line RW is connected to a reading unit that reads a signal from the pixel 30. The reading unit includes, for example, an AD conversion unit that converts an analog signal output from the pixel 30 into a digital signal. The output line RW is connected to a current source CS that supplies current to the amplification transistor TA and the like in the pixel 30.

As described above, the vertical control unit VC and the horizontal control unit HC control the voltage of the control signal to the vertical selection line VS and the horizontal selection line HS to thereby control any one or more pixels in the pixel block BC2. A signal (Gb, Z2, R, Gr) (output of the amplification transistor TA) is output to the output line RW. The reading unit reads signals from the pixels (Gb, Z2, R, Gr) in the pixel block BC2.

The image pickup operation including the reset operation of the pixels 30 of the image pickup device 3 of the present embodiment is almost the same as that of the conventional 4-transistor type CMOS image pickup device. That is, prior to the exposure operation for imaging or focus detection, the reset transistor TR and the transfer transistor TX are brought into conduction with the power supply voltage VDD, and the FD region FD and the photodiode PD are reset to the power supply voltage VDD. Thereafter, the transfer transistor TX is turned off, and exposure for imaging or focus detection is performed by the photodiode PD.

The reading unit of the image sensor 3 according to the present embodiment can read an addition signal obtained by adding (summing and binning) signals of an arbitrary number of pixels 30 in one pixel block BC.
For example, when a through image (live view image) is displayed on the display unit 6 or when moving image shooting is performed, the control unit 4 generates image data based on an addition signal obtained by adding signals from a plurality of pixels 30. The image data based on the addition signal is image data having a smaller number of pixels than the total number of pixels of the image sensor. Moreover, since the noise mixed in the signal of each pixel 30 is smoothed by adding the signals of the plurality of pixels 30, the control unit 4 can generate an image with less noise. In order to add the signals of the arbitrary number of pixels 30 in the pixel block BC, the vertical control unit VC and the horizontal control unit HC simultaneously output the signals of the arbitrary number of pixels 30 to the output line RW. The reading unit reads signals of an arbitrary number of pixels 30 in the pixel block BC that are simultaneously output to the output line RW as an addition signal. Note that an arbitrary number of pixels 30 may not output signals to the output line RW at the same time. The arbitrary number of pixels 30 may output each other's signals while the signals are output to the output line RW.

Note that, in the image sensor 3 of the present embodiment, the signals of the plurality of pixels 30 are so-called source follower addition. Therefore, the value of the signal read by the reading unit is not the sum of the signal values of each pixel 30, but is close to the average value of the signal values of each pixel 30.

The plurality of pixels 30 that output the addition signal are preferably pixels of the same color. The vertical control unit VC and the horizontal control unit HC control the voltage of the control signal to the vertical selection line VS and the horizontal selection line HS to select a plurality of pixels 30 of the same color in one pixel block BC, and The signal is output to the output line RW via the vertical selection transistor TV and the horizontal selection transistor TH. The reading unit reads the signal of the selected pixel 30 of the same color output to the output line RW as an addition signal.

With reference to FIG. 2B, control by the vertical control unit VC and the horizontal control unit HC and signal reading by the reading unit will be described.
For example, when the signals of all the R pixels R in the pixel block BC2 illustrated in FIG. 2B are added and output, the vertical control unit VC applies the vertical selection lines VS5 and VS7 connected to the R pixels to Send a signal to turn on the vertical selection transistor TV. The vertical control unit VC supplies a power supply voltage, for example. On the other hand, the vertical control unit VC sends a signal that makes the vertical selection transistor TV non-conductive to the vertical selection lines VS6 and VS8 that are not connected to the R pixel. The vertical control unit VC supplies a ground voltage, for example.

Then, the horizontal control unit HC sends a signal for making the horizontal selection transistor TH2 conductive to the horizontal selection lines HS2 and HS4 connected to the R pixel, and horizontally to the horizontal selection lines HS1 and HS3 not connected to the R pixel. A signal for turning off the selection transistor TH2 is sent.
Under the control of the vertical control unit VC and the horizontal control unit HC, the four R pixels R arranged at the positions where the vertical selection lines VS5 and VS7 and the horizontal selection lines HS2 and HS4 intersect with each other are connected to the vertical selection transistor TV. Both of the horizontal selection transistors TH2 become conductive. Accordingly, the signals of these four R pixels R are simultaneously output to the output line RW. The signals of the four R pixels R are added by being simultaneously output to the output line RW. The reading unit reads the signals of the four R pixels R output to the output line RW as addition signals.

The horizontal control unit HC sends a signal for turning on the horizontal selection transistor TH2 only to the horizontal selection line HS2, and sends a signal for turning off the horizontal selection transistor TH2 to the horizontal selection lines HS other than the horizontal selection line HS2. The signals of the two R pixels R arranged at the position where the horizontal selection line HS2 and the vertical selection lines VS5 and VS7 intersect can be simultaneously output to the output line RW. The signals of the two R pixels R described above are added by being simultaneously output to the output line RW. Thereby, the reading unit can read the addition signal of the two R pixels R.

Alternatively, the vertical control unit VC sends a signal for making the vertical selection transistor TV conductive only to the vertical selection line VS5, so that the vertical selection line VS5 and the horizontal selection lines HS2 and HS4 are arranged at positions where they intersect. The signals of the two R pixels R can be simultaneously output to the output line RW. The signals of the two R pixels R described above are added by being simultaneously output to the output line RW. Thereby, the reading unit can read the addition signal of the two R pixels R.

Further, the vertical control unit VC and the horizontal control unit HC can output a signal of only one R pixel R in one pixel block BC2 to the output line RW. Thereby, the reading unit can read the signal of only one R pixel R. In this case, the vertical control unit VC may send a signal for conducting the vertical selection transistor TV to the vertical selection line VS5 or VS7 and send a signal for conducting the horizontal selection transistor TH2 to the two horizontal lines HS2 or HS4.

In the pixel block BC2, two of the four B pixels B are replaced with the special pixels Z1 and Z2, but the readout of the signal of the B pixel B is substantially the same as the readout of the signal of the R pixel R described above. .
When adding and outputting the signals of all the B pixels B in the pixel block BC2, the horizontal control unit HC sends a signal for making the horizontal selection transistor TH2 conductive to the horizontal selection line HS1. Further, the horizontal control unit HC sends a signal for turning off the horizontal selection transistor TH2 to the horizontal selection lines HS other than the horizontal selection line HS1, and a signal for turning off the special horizontal selection transistor TH1 to the special horizontal selection line ZS. Send.

Then, the vertical control unit VC sends a signal for turning on the vertical selection transistor TV to the vertical selection lines VS6 and VS8, so that the signals of the two B pixels B are simultaneously output to the output line RW. The signals of the two B pixels B are added to the output line RW at the same time. The reading unit reads the addition signal of the two B pixels B. Further, the vertical control unit VC sends a signal for turning on the vertical selection transistor TV to the vertical selection line VS6 or VS8, so that the reading unit can read the signal of one B pixel B.

The horizontal control unit HC sends a signal for turning off the special horizontal selection transistor TH1 to the special horizontal selection line ZS, so that the signals of the special pixels Z1 and Z2 are not output to the output line RW. Therefore, the signals of the special pixels Z1 and Z2 are not mixed into the signal of the B pixel B.

The horizontal selection line HS3 arranged in parallel with the special horizontal selection line ZS is not connected to the special horizontal selection transistor TH1 in the special pixels Z1 and Z2. Therefore, no matter what signal the horizontal control unit HC sends to the horizontal selection line HS3, the signals of the special pixels Z1 and Z2 are not mixed into the signal of the B pixel B.
However, since the horizontal selection line HS3 is shared with other pixel blocks BC such as the pixel block BC1 adjacent to the pixel block BC2 in the x direction, the signal sent from the horizontal control unit HC to the horizontal selection line HS3 It is preferable to send a signal suitable for reading in the pixel block BC.

Reading signals of the G pixel G (G pixel Gb and G pixel Gr) in the pixel block BC2 is the same as reading of the signals of the R pixel R and the B pixel B described above. The vertical control unit VC and the horizontal control unit HC send a signal for controlling the vertical selection transistor TV and the horizontal selection transistor TH2 to a selection line connected to the G pixel G to be read out of the vertical selection line VS and the horizontal selection line HS. Thereby, the reading unit can read the signal of one G pixel G or the addition signal of a plurality of G pixels G.
At this time, the horizontal control unit HC makes the special horizontal selection transistor TH1 non-conductive to the special horizontal selection line ZS so that the signals of the special pixels Z1 and Z2 are not mixed into the signal of the G pixel G output to the output line RW. Send a signal.

When the signal of the special pixel Z1 is read, the vertical control unit VC and the horizontal control unit HC apply the vertical selection transistor TV and the special horizontal selection transistor to the vertical selection line VS6 and the special horizontal selection line ZS connected to the special pixel Z1, respectively. A signal for turning on TH1 is sent to output the signal of the special pixel Z1 to the output line RW. When the signal of the special pixel Z2 is read, the vertical control unit VC and the horizontal control unit HC are connected to the vertical selection line VS8 and the special horizontal selection line ZS connected to the special pixel Z2, respectively, with the vertical selection transistor TV and the special horizontal selection line. A signal for turning on the selection transistor TH1 is sent to output the signal of the special pixel Z2 to the output line RW. The reading unit reads the signal of the special pixel Z1 or Z2 output to the output line RW. When reading the signal of the special pixel Z1 or Z2, the vertical control unit VC and the horizontal control unit HC are connected to the vertical selection line VS and the horizontal selection line HS other than the vertical selection line VS6 and the vertical selection line VS8, respectively. A signal for turning off the horizontal selection transistor TH2 is sent.

When the signals of the special pixels Z1 and Z2 are added and read, the vertical control unit VC and the horizontal control unit HC are connected to the vertical selection line VS6, the vertical selection line VS8, and the special horizontal selection line ZS, respectively. A signal for turning on the horizontal selection transistor TH1 is sent, and the signals of the special pixels Z1 and Z2 are simultaneously output to the output line RW. The signals of the special pixels Z1 and Z2 are added by being simultaneously output to the output line RW. Thereby, the reading unit reads the addition signal of the special pixels Z1 and Z2.

The reading of the signal of the pixel 30 in the pixel block BC2 has been described above. The same applies to the other pixel blocks BC. The signal of each pixel 30 in each pixel block BC is output to an output line RW provided in each pixel block BC, and is read by the reading unit. Note that the vertical selection line VS, the horizontal selection line HS, and the special horizontal selection line ZS may be shared by a plurality of pixel blocks BC. For example, the horizontal selection lines HS1 to HS4 may be connected to each pixel 30 in another pixel block BC arranged in the x direction with respect to the pixel block BC2, like the pixel block BC1. Further, the vertical selection lines VS5 to VS8 may be connected to each pixel 30 in another pixel block BC arranged in the y direction with respect to the pixel block BC2.
A signal read by the reading unit of each pixel block BC is output from the image sensor 3 via an output circuit (not shown).

Note that the order of reading out the signals from the special pixel ZZ and the imaging pixel 30c is arbitrary. For example, the vertical control unit VC and the horizontal control unit HC first select the special pixels Z1 and Z2 in order via the vertical selection line VS and the horizontal selection line HS, and the reading unit reads the signal. Thereafter, the vertical control unit VC and the horizontal control unit HC select the imaging pixel 30c via the vertical selection line VS and the horizontal selection line HS, and the reading unit reads the signal.

Since the number of special pixels ZZ (two of Z1 and Z2) in the pixel block BC2 is smaller than the number of pixels of the imaging pixel 30c (14 in total including Gb, Gr, R, and B), the signal of the special pixel ZZ The time required for reading is shorter than the time required for reading the signal of the imaging pixel. That is, the signal readout from the special pixel ZZ can be performed at a higher speed than the signal readout from the imaging pixel 30c. For example, when the special pixel ZZ is an AF pixel, the control unit 4 can perform focus detection at high speed by reading the signal of the special pixel ZZ before reading the signal of the imaging pixel 30c. .
Further, two readout units may be provided in one pixel block BC. By connecting two readout units to one output line RW, each of the two readout units may read out the signal of the special pixel ZZ and the signal of the imaging pixel 30c. Thereby, the reading unit can read the signal of the special pixel ZZ and the signal of the imaging pixel 30c under respective reading conditions such as optimum gain.

FIG. 4 is a diagram showing a cross section of the pixel 30 portion of the image sensor 3 of the present embodiment. In FIG. 4, only a part of the cross section of the entire image sensor 3 is shown. The x direction and the z direction shown in FIG. 4 are the same as the directions shown in FIG. The image sensor 3 is a so-called back-illuminated image sensor. The image sensor 3 photoelectrically converts light incident from above in the drawing. The image sensor 3 includes a first semiconductor substrate 7 and a second semiconductor substrate 8.

As described above, the image sensor 3 has a plurality of pixels 30. One pixel 30 includes a pixel upper part 30 x provided on the first semiconductor substrate 7 and a pixel lower part 30 y provided on the second semiconductor substrate 8. One pixel upper portion 30x includes one micro lens 74, one color filter 73, one light receiving portion 31 of a photodiode PD, and the like.

The first semiconductor substrate 7 includes a light receiving layer 71 including the light receiving portion 31 of the photodiode PD included in the pixel upper portion 30x, and a wiring layer 72 in which transistors such as the transfer transistor TX and the amplification transistor TA are formed. The light receiving layer 71 is disposed on the opposite side (back side) of the wiring layer 72 of the first semiconductor substrate 7. In the light receiving layer 71, a plurality of light receiving portions 31 are two-dimensionally arranged.

Since the pixel upper portion 30x includes the light receiving portion 31 that is a portion that photoelectrically converts incident light, it can also be interpreted as an imaging portion.
The second semiconductor substrate 8 includes a vertical selection transistor TV, a horizontal selection transistor TH2, a special horizontal selection transistor TH1, a vertical selection line VS, a horizontal selection line HS, a special horizontal selection line ZS, a reading unit, A current source CS and the like are arranged.

A plurality of bumps 75 are arranged on the surface of the wiring layer 72. A plurality of bumps 76 corresponding to the plurality of bumps 75 are arranged on the surface of the second semiconductor substrate 8 facing the wiring layer 72. The plurality of bumps 75 and the plurality of bumps 76 are joined to each other. The first semiconductor substrate 7 and the second semiconductor substrate 8 are electrically connected via the plurality of bumps 75 and the plurality of bumps 76.

The configuration of the circuit elements disposed on the first semiconductor substrate 7 and the second semiconductor substrate 8 described above is an example, and some of the components are the first semiconductor substrate 7 and the second semiconductor substrate 8. You may arrange in either. For example, the light receiving layer 71 including the light receiving unit 31 of the photodiode PD, the transfer transistor TX, the amplification transistor TA, and the vertical selection transistor TA are formed on the first semiconductor substrate 7, and the horizontal selection transistor TH2, the special horizontal selection transistor TH1, The horizontal selection line HS, the special horizontal selection line ZS, the reading unit, and the current source CS may be arranged on the second semiconductor substrate 8.

The light receiving layer 71 including the light receiving unit 31 of the photodiode PD, the transfer transistor TX, the amplification transistor TA, the vertical selection transistor TA, the horizontal selection transistor TH2, the special horizontal selection transistor TH1, the horizontal selection line HS, and the special horizontal selection line ZS. The read unit and the current source CS may be arranged on the second semiconductor substrate 8 formed on the first semiconductor substrate 7.
The vertical control unit VC and the horizontal control unit HC may be arranged on either the first semiconductor substrate 7 or the second semiconductor substrate 8.

However, if many circuit elements are arranged on the first semiconductor substrate 7, the area or volume for arranging the light receiving unit 31 on the first semiconductor substrate 7 cannot be sufficiently secured. It is preferable to arrange on the semiconductor substrate 8.
The color filter 73 of each pixel 30 is provided with a color filter that matches the spectral sensitivity characteristics of each pixel.

Further, the color filter 73 is also arranged in the special pixel ZZ among the pixels 30. When the special pixel ZZ is an AF pixel, a G color filter is provided as the color filter 73. Note that the color filter 73 provided in the special pixel ZZ may be a filter that transmits the entire wavelength range of incident light. Further, the color filter 73 provided in the special pixel ZZ may be a color filter having a spectral characteristic different from any of the color filters 73 arranged in the imaging pixel 30c.

When the special pixel ZZ is a pixel for receiving infrared light, the color filter 73 has high infrared light transmittance and low visible light transmittance. Further, when the special pixel ZZ is a pixel for receiving visible light, the color filter 73 has a high transmittance in the entire wavelength region of visible light.

Even if the sensitivity of the special pixel ZZ is made different from the sensitivity of the imaging pixel 30c, for example, by making the average transmittance of the color filter 73 of the special pixel ZZ different from the average transmittance of the color filter 73 of the imaging pixel 30c. Good. Here, the average transmittance refers to the average of the transmittance with respect to all wavelengths of light photoelectrically converted by the light receiving unit 31.
The sensitivity of the special pixel ZZ is such that the area of the light receiving unit 31 of the special pixel ZZ is different from the area of the light receiving unit 31 of the imaging pixel 30c, or the condition of ion implantation into the light receiving unit 31 is different. It may be different from the sensitivity.
By making the sensitivity of the special pixel ZZ and the imaging pixel 30c different, the special pixel ZZ and the imaging pixel 30c output different signals. By generating image data based on different signals, the image quality (resolution, gradation, color) of the image can be improved.

FIG. 5 is a diagram illustrating an example when the special pixel ZZ is an AF pixel. In FIG. 5, the second semiconductor substrate 8 is omitted from the cross-sectional view of the image sensor 3 illustrated in FIG. 4.
The special pixel Z <b> 1 is provided with a light shielding portion 75 </ b> R that shields the right side of the light receiving portion 31 at the boundary between the color filter 73 and the first semiconductor substrate 7. On the other hand, the special pixel Z2 is provided with a light shielding portion 75L that shields the left side of the light receiving portion 31 at the boundary portion.

Of the light incident on the special pixel Z1, the light LL that is inclined in the −x direction with respect to the direction PL perpendicular to the incident surface of the image sensor 3 is shielded by the light shielding portion 75R. On the other hand, of the light incident on the special pixel Z2, the light LR that is inclined in the + x direction with respect to the direction PL perpendicular to the incident surface of the image sensor 3 is shielded by the light shielding portion 75L.
As a result, the special pixels Z1 and Z2 have lower sensitivity to light incident from different incident directions, and conversely, the sensitivity to light incident from different incident directions is relatively high.

If this imaging element 3 is applied to the imaging apparatus of FIG. 1, the special pixels Z1 and Z2 are elements that have high sensitivity to light passing through different positions on the pupil plane of the imaging optical system 2, and therefore the image plane phase difference. It functions as a pixel for focus detection.
The position where the

light shielding portions

75R and 75L are provided is not limited to the boundary portion between the color filter 73 and the first semiconductor substrate 7 described above, and is provided somewhere between the microlens 74 and the first semiconductor substrate 7. Just do it.

In the embodiments of the image sensor described above, the arrangement of the pixels 30 is not necessarily limited to the Bayer arrangement. Further, the horizontal selection line HS and the special horizontal selection line ZS may extend in the short side direction instead of the long side direction of the image sensor 3, and the vertical selection line VS does not extend in the short side direction of the image sensor 3. It may extend in the direction.
Further, the horizontal selection line HS, the special horizontal selection line ZS, and the vertical selection line VS that control the output of the signal of each pixel 30 do not extend in the horizontal direction (x direction) and the vertical direction (y direction). May be. The horizontal selection line HS, special horizontal selection line ZS, and vertical selection line VS may not be shared by the plurality of pixels 30.

According to the embodiment described above, the following operational effects can be obtained.
(1) The imaging device 3 of the above embodiment is generated by the first photoelectric conversion unit (photodiode PD in the first pixel ZZ) that photoelectrically converts light to generate charges, and the first photoelectric conversion unit. A first output unit TH1 that outputs a first signal based on charges, a plurality of second photoelectric conversion units (photodiodes PD in the imaging pixel 30c) that photoelectrically convert light to generate charges, and a second photoelectric conversion unit A plurality of second output units TH2 for outputting a second signal based on the electric charge generated in step S1, a first output unit TH1 and a plurality of second output units TH2, and at least one of the first signal and the second signal is connected. One output line RW, a first control line (special horizontal selection line ZS) for controlling the output of the first signal from the first output unit TH1 to the output line RW, and a plurality of second output units TH2. For controlling the output of the second signal to the output line RW from It has 2 control lines (horizontal selection line HS), a.
With such a configuration, it is possible to select 30 outputs of any one or a plurality of pixels among a plurality of pixels connected to the output line RW and output them to the output line RW.

(2) Furthermore, the first output unit TH1 is configured to output the first signal at a timing different from the output of the second signal by the second output unit TH2, thereby allowing the first signal based on the first photoelectric conversion unit to be output. Alternatively, the reading of the second signal based on the second photoelectric conversion unit can be performed in an arbitrary order.
(3) Further, while the first output unit TH1 outputs the first signal, the second output unit TH2 is controlled via the second control line (horizontal selection line HS) so as not to output the second signal. By doing so, mixing of the second signal based on the second photoelectric conversion unit into the output of the first signal based on the first photoelectric conversion unit can be prevented, and a more accurate signal can be output.

(4) Further, while the second output unit TH2 outputs the second signal, the first output unit TH1 is controlled via the first control line (special horizontal selection line ZS) so as not to output the first signal. By doing so, mixing of the first signal based on the first photoelectric conversion unit into the output of the second signal based on the second photoelectric conversion unit can be prevented, and a more accurate signal can be output.
(5) Furthermore, while the plurality of second output units TH2 output the plurality of second signals simultaneously, the first output unit TH1 does not output the first signal via the first control line (special horizontal selection line ZS). By adopting such a configuration, it is possible to prevent mixing of the first signal based on the first photoelectric conversion unit into the output of the second signal based on the second photoelectric conversion unit, and to output a more accurate signal. .

(6) Third control for controlling at least one of the output of the first signal from the first output unit TH1 to the output line RW and the output of the second signal from the second output unit TH2 to the output line RW. Line (vertical selection line VS), the first output unit TH1 is controlled via the first control line (special horizontal selection line ZS) and the third control line (vertical selection line VS), the second output unit TH2 is configured to be controlled via the second control line (horizontal selection line HS) and the third control line (vertical selection line VS), so that the pixel 30 that reads the output from the output line RW is more arbitrary. Can be selected.
(7) Furthermore, the first control line (special horizontal selection line ZS) and the second control line (horizontal selection line HS) are provided in the first direction, and the third control line (vertical selection line VS) is the first control line. With the configuration provided in the second direction intersecting with the one direction, selection of the pixel 30 that reads the output from the output line RW can be easily performed.

(8) Furthermore, by having a light-shielding part that shields a part of the light incident on the first photoelectric conversion part, the relationship between the incident angle of the incident light to the first photoelectric conversion part and the sensitivity is made incident. The relationship between the incident angle of light to the second photoelectric conversion unit and sensitivity can be made different.
(9) Further, the first output unit TH1 outputs a first signal used for focus detection, and the second output unit TH2 outputs a second signal used for image generation, whereby the first pixel ZZ is configured. Can be used as pixels for detecting the in-plane phase difference focus.

(10) Furthermore, the first photoelectric conversion unit is optimal for each of the first pixel ZZ and the second pixel (imaging pixel 30c) by adopting a configuration that is a photoelectric conversion unit having a sensitivity different from that of the second photoelectric conversion unit. Sensitivity can be given.
(11) Furthermore, the second photoelectric conversion unit can have the image sensor 3 have a desired spectral sensitivity by performing a photoelectric conversion on the light transmitted through the first filter having the first spectral characteristic.
(12) Furthermore, the first photoelectric conversion unit is configured to photoelectrically convert the light transmitted through the second filter having the second spectral characteristic different from the first spectral characteristic, and thereby to the first pixel (special pixel ZZ). Can have an optimum spectral sensitivity.

(13) Furthermore, the first control line (special horizontal selection line ZS) and the second control line (horizontal selection line HS) are connected, and the output of the first signal from the first output unit TH1 to the output line RW; By providing a control unit (selection transistors TV, TH1, TH2) for controlling the output of the second signal from the second output unit TH2 to the output line RW, the output from the first output unit TH1 to the output line RW And the control of the output from the second output part TH2 to the output line RW can be performed more simply.
(14) Further, the control unit (selection transistors TV, TH1, TH2) may be stacked with an imaging unit (pixel upper portion 30x) having a first photoelectric conversion unit and a plurality of second photoelectric conversion units. This eliminates the need to dispose the control unit (selection transistors TV, TH1, TH2) on the first semiconductor substrate 7 on which the image capturing unit (pixel upper portion 30x) is disposed, and the light receiving unit in the image capturing unit (pixel upper portion 30x). The area and volume of 31 can be secured to a sufficient size, and the sensitivity of the image sensor 3 can be improved.

(15) Further, a readout unit that is stacked with an imaging unit (pixel upper portion 30x) having a first photoelectric conversion unit and a plurality of second photoelectric conversion units and reads at least one of the first signal and the second signal from the output line RW. It is good also as a structure provided with ADC. In this configuration, since the readout unit ADC is stacked on the second semiconductor substrate 8 or the like different from the first semiconductor substrate 7 having the imaging unit (pixel upper portion 30x), the readout unit ADC is disposed in the imaging unit (pixel upper portion 30x). The area and volume of the light receiving unit 31 can be secured to a sufficient size, and the sensitivity of the image sensor 3 can be improved.
(16) Furthermore, since the reading unit ADC is a conversion unit that converts at least one of the first signal and the second signal from an analog signal to a digital signal, the reading unit ADC generates a digital signal. Thus, it becomes easy to design a signal processing system after the reading unit ADC.

(17) Further, a first readout unit that is stacked with an imaging unit (pixel upper portion 30x) having a first photoelectric conversion unit and a plurality of second photoelectric conversion units, and that reads a first signal from the output line RW, and an output line RW It can also be set as the structure provided with the 2nd reading part which reads a 2nd signal. With this configuration, since the first photoelectric conversion unit and the plurality of second photoelectric conversion units can be read out by separate reading units, optimum reading can be performed for each pixel.
(18) Further, the first reading unit is a first conversion unit that converts the first signal from an analog signal to a digital signal, and the second reading unit is a second conversion unit that converts the second signal from an analog signal to a digital signal. It can be set as the structure which is. With this configuration, the outputs of the first photoelectric conversion unit and the plurality of second photoelectric conversion units can be converted by separate analog-digital converters, and optimal readout can be performed for each pixel.

(19) Further, the first output part TH1 and the second output part TH2 are selection transistors, and the first control line (special horizontal selection line ZS) and the second control line (horizontal selection line HS) are selection transistors. It can be set as the structure which is a control line for controlling. With this configuration, the first output portion TH1 and the second output portion TH2 can be formed with a simple configuration.
(20) The imaging device of the embodiment includes the imaging device 3 having any one of the above configurations (1) to (19) and the generation unit 4 that generates image data based on the second signal.
With this configuration, the output of any one or a plurality of pixels 30 among the pixels 30 connected to the output line RW of the image sensor 3 can be selected, and the output can be output to the output line RW and read out. .

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. In addition, each embodiment and modification may be applied alone or in combination. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

The disclosure of the following priority application is hereby incorporated by reference.
Japanese Patent Application 2018-99061 (filed on May 23, 2018)

1: imaging device, 2: imaging lens, 3: imaging element, 4: generation unit, 5: lens driving unit,
7: first semiconductor substrate, 8: second semiconductor substrate, BC, BC1, BC2: pixel block, HC: horizontal control unit, VC: vertical control unit, pixel 30, Gr, Gb: G pixel, R: R pixel, B: B pixel, Z1, Z2: Special pixel, VS, VS1 to HS8: Vertical selection line, HS, HS1 to HS4: Horizontal selection line, ZS: Special horizontal selection line, PD: Photodiode, TX: Transfer transistor, TR : Reset transistor, TA: amplification transistor, TV: vertical selection transistor, TH1: special horizontal selection transistor, TH2: horizontal selection transistor, RW: readout line, ADC: readout unit, 31: photosensitive unit, 73: color filter

Claims

A first photoelectric conversion unit that photoelectrically converts light to generate charges;
A first output unit that outputs a first signal based on the charge generated by the first photoelectric conversion unit;
A plurality of second photoelectric conversion units that photoelectrically convert light to generate charges;
A plurality of second output units for outputting a second signal based on the electric charge generated by the second photoelectric conversion unit;
An output line that connects the first output unit and the plurality of second output units, and outputs at least one of the first signal and the second signal;
A first control line for controlling the output of the first signal from the first output unit to the output line;
A second control line for controlling the output of the second signal from the plurality of second output units to the output line;
An imaging device comprising:
The imaging device according to claim 1,
The first output unit outputs the first signal at a timing different from the output of the second signal by the second output unit.
The imaging device according to claim 1 or 2,
The imaging device controlled via the second control line so that the second output unit does not output the second signal while the first output unit outputs the first signal.
In the imaging device according to any one of claims 1 to 3,
The imaging device controlled via the first control line so that the first output unit does not output the first signal while the second output unit outputs the second signal.
In the imaging device according to any one of claims 1 to 4,
An imaging device that is controlled via the first control line so that the first output unit does not output the first signal while the plurality of second output units simultaneously output the plurality of second signals.
In the imaging device according to any one of claims 1 to 5,
A third control line for controlling at least one of the output of the first signal from the first output unit to the output line and the output of the second signal from the second output unit to the output line; ,
The first output unit is controlled via the first control line and the third control line,
The second output unit is an imaging device controlled via the second control line and the third control line.
The image sensor according to claim 6, wherein
The first control line and the second control line are provided in a first direction,
The third control line is an image sensor provided in a second direction intersecting the first direction.
In the imaging device according to any one of claims 1 to 7,
An imaging device having a light shielding portion that shields part of light incident on the first photoelectric conversion portion.
In the imaging device according to any one of claims 1 to 8,
The first output unit outputs the first signal used for focus detection,
The second output unit is an image sensor that outputs the second signal used for image generation.
In the imaging device according to any one of claims 1 to 9,
The imaging device, wherein the first photoelectric conversion unit is a photoelectric conversion unit having a sensitivity different from that of the second photoelectric conversion unit.
In the imaging device according to any one of claims 1 to 10,
The second photoelectric conversion unit is an image sensor that photoelectrically converts light transmitted through a first filter having a first spectral characteristic.
In the imaging device according to any one of claims 1 to 11,
The first photoelectric conversion unit is an imaging device that photoelectrically converts light transmitted through a second filter having a second spectral characteristic different from the first spectral characteristic.
The imaging device according to any one of claims 1 to 12,
The first control line and the second control line are connected, the output of the first signal from the first output unit to the output line, and the second signal from the second output unit to the output line An image sensor comprising a control unit for controlling the output of the image sensor.
The image sensor according to claim 13, wherein
The said control part is an image pick-up element laminated | stacked with the imaging part which has a said 1st photoelectric conversion part and several said 2nd photoelectric conversion part.
In the image sensor according to any one of claims 1 to 14,
An imaging device comprising: a readout unit that is stacked with an imaging unit having the first photoelectric conversion unit and a plurality of the second photoelectric conversion units, and reads at least one of the first signal and the second signal from the output line.
The image sensor according to claim 15, wherein
The imaging device, wherein the reading unit is a conversion unit that converts at least one of the first signal and the second signal from an analog signal to a digital signal.
In the image sensor according to any one of claims 1 to 14,
A first readout unit that is stacked with an imaging unit including the first photoelectric conversion unit and a plurality of the second photoelectric conversion units, and that reads the first signal from the output line; and a second readout unit that reads the second signal from the output line. An image sensor comprising two reading units.
The image sensor according to claim 17,
The first reading unit is a first conversion unit that converts the first signal from an analog signal to a digital signal;
The imaging device, wherein the second reading unit is a second conversion unit that converts the second signal from an analog signal to a digital signal.
In the imaging device according to any one of claims 1 to 18,
The first output unit and the second output unit are selection transistors,
The imaging device, wherein the first control line and the second control line are control lines for controlling the selection transistor.
The image sensor according to any one of claims 1 to 19,
A generating unit that generates image data based on the second signal;
An imaging apparatus comprising: